Prosthetic heart valve

ABSTRACT

A prosthetic heart valve includes a frame, a valvular structure, and a skirt. The frame is movable between collapsed and expanded configurations and includes struts disposed between inflow and outflow ends, apices disposed at the inflow end formed by intersections of two or more struts, and junctions disposed between the apices and the outflow end and formed by intersections of two or more struts. The apices are circumferentially offset from the junctions. The valvular structure is positioned within and secured to the frame. The skirt is secured to the frame and includes a first edge portion and a second edge portion. The first edge portion is secured to the frame at the apices. The second edge portion is secured to the frame at the junctions. The skirt is configured to retract inwardly between the apices when the frame is moved from the radially expanded configuration to the radially collapsed configuration.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/986,077, filed May 22, 2018, issuing as U.S. Pat. No. 11,051,937,which is a continuation of U.S. patent application Ser. No. 15/209,642,filed Jul. 13, 2016, now U.S. Pat. No. 9,974,650, which claims thebenefit of U.S. Provisional Application No. 62/192,515, filed on Jul.14, 2015, the entire disclosures of which are incorporated by referenceherein.

FIELD

The present disclosure relates to implantable, expandable prostheticdevices and to methods and apparatuses for such prosthetic devices.

BACKGROUND

The human heart can suffer from various valvular diseases. Thesevalvular diseases can result in significant malfunctioning of the heartand ultimately require replacement of the native valve with anartificial valve. There are a number of known artificial valves and anumber of known methods of implanting these artificial valves in humans.Because of the drawbacks associated with conventional open-heartsurgery, percutaneous and minimally-invasive surgical approaches aregarnering intense attention. In one technique, a prosthetic valve isconfigured to be implanted in a much less invasive procedure by way ofcatheterization. For example, collapsible transcatheter prosthetic heartvalves can be crimped to a compressed state and percutaneouslyintroduced in the compressed state on a catheter and expanded to afunctional size at the desired position by balloon inflation or byutilization of a self-expanding frame or stent.

A prosthetic valve for use in such a procedure can include a radiallycollapsible and expandable frame to which leaflets of the prostheticvalve can be coupled. For example, U.S. Pat. Nos. 6,730,118, 7,393,360,7,510,575, and 7,993,394, which are incorporated herein by reference,describe exemplary collapsible transcatheter prosthetic heart valves.

A prosthetic valve for use in such a procedure can include a radiallycollapsible and expandable frame to which leaflets of the prostheticvalve can be coupled, and which can be percutaneously introduced in acollapsed configuration on a catheter and expanded in the desiredposition by balloon inflation or by utilization of a self-expandingframe or stent. A challenge in catheter-implanted prosthetic valves iscontrol of perivalvular leakage around the valve, which can occur for aperiod of time following initial implantation. An additional challengeincludes the process of crimping such a prosthetic valve to a profilesuitable for percutaneous delivery to a subject.

SUMMARY

Embodiments of a radially collapsible and expandable prosthetic valveare disclosed herein that include an improved outer skirt for reducingperivalvular leakage, as well as related methods and apparatusesincluding such prosthetic valves. In several embodiments, the disclosedprosthetic valves are configured as replacement heart valves forimplantation into a subject.

In one representative embodiment, an implantable prosthetic valve cancomprise an annular frame comprising an inflow end and an outflow endand being radially collapsible and expandable between a radiallycollapsed configuration and a radially expanded configuration, the framedefining an axial direction extending from the inflow end to the outflowend, a leaflet structure positioned within the frame and securedthereto, and an annular outer skirt positioned around an outer surfaceof the frame, wherein the outer skirt comprises an inflow edge securedto the frame at a first location, an outflow edge comprising a pluralityof alternating projections and notches, wherein the projections aresecured to the frame at a second location, and the notches are notdirectly secured to the frame, an intermediate portion between theinflow edge and the outflow edge that comprises a plurality of openings.

In some embodiments, when the frame is in the collapsed configuration,the axial distance between the inflow edge of the outer skirt and theoutflow edge of the outer skirt can be greater than when the valve is inthe expanded configuration, increasing tension of the intermediateportion of the outer skirt.

In some embodiments, the outer skirt can comprise a first height, andthe frame in the radially expanded configuration can comprise a secondheight, and wherein a ratio of the first height to the second height canbe about 0.75 to about 0.95. In some embodiments, the ratio of the firstheight to the second height can be about 0.86.

In some embodiments, the outer skirt can comprise a plurality of axiallyextending creases. In some embodiments, the creases are formed bysuturing and/or ultrasonic welding portions of the outer skirt to eachother.

In some embodiments, each of the openings of the outer skirt can becircumferentially aligned with a respective crease of the outer skirt.In some embodiments, each of the creases of the outer skirt can becircumferentially aligned with a respective projection of the outerskirt.

In some embodiments, the outer skirt can be positioned relative to theframe such that each of the creases of the outer skirt iscircumferentially positioned between a respective pair of apices formedby struts at the inflow end of the frame. In some embodiments, each ofthe creases can be positioned equidistantly between a respective pair ofapices.

In some embodiments, the prosthetic valve can further comprise anannular inner skirt positioned around an inner surface of the frame,wherein the inner skirt can comprise an inflow edge secured to the frameat a third location, an outflow edge secured to the frame at a fourthlocation. In some of those embodiments, the inflow edge of the outerskirt can be attached to the inflow edge of the inner skirt. In suchembodiments, the inflow edge of the outer skirt can be attached to theinflow edge of the inner skirt with ultrasonic welding.

In some embodiments, at least a portion of the outer skirt can beconfigured to retract radially within the frame when the frame is theradially collapsed configuration. In some embodiments, the outer skirtcan be configured such that blood can flow through the openings and thenotches of the outer skirt and blood can flow through a space betweenthe outer skirt and the frame. In some embodiments, the outer skirt isattached to the frame such that each of the projections of the outerskirt is circumferentially positioned between a respective pair ofapices formed by struts at the inflow end of the frame.

In another representative embodiment, an assembly for implanting aprosthetic heart valve in a patient's body is provided. The assembly cancomprise a delivery apparatus comprising an elongate shaft, and aprosthetic heart valve mounted on the shaft in a radially collapsedconfiguration for delivery into the body.

In another representative embodiment, a method of manufacturing aprosthetic valve is provided. The method can comprise forming at leastone permanent crease in an annular outer skirt of the prosthetic valve,and securing the outer skirt to an annular frame of the prostheticvalve. In some embodiments, forming the at least one crease comprisessuturing and/or ultrasonic welding portions of the outer skirt to eachother.

In some embodiments, the method can further comprise forming at leastone opening in the outer skirt, wherein the at least one opening iscircumferentially aligned with a respective at least one crease. In someembodiments, the method can further comprise positioning the outer skirtrelative to an annular frame such that the at least one crease iscircumferentially disposed between struts of the frame.

In another representative embodiment, an implantable prosthetic valvecan comprise an annular frame comprising an inflow end and an outflowend and being radially collapsible and expandable between a radiallycollapsed configuration and a radially expanded configuration, the framedefining an axial direction extending from the inflow end to the outflowend, a leaflet structure positioned within the frame and securedthereto, and an annular outer skirt positioned around an outer surfaceof the frame, wherein the outer skirt comprises an inflow edge securedto the frame at a first location, an outflow edge secured to the frameat a second location, a plurality of axially extending creases, whereinthe creases are configured to cause at least a portion of the outerskirt to retract radially within the frame when the frame is radiallycollapsed from the expanded configuration.

In some embodiments, the outer skirt can further comprise anintermediate portion between the inflow edge and the outflow edge thatcomprises a plurality of openings.

The foregoing and other features and advantages of this disclosure willbecome more apparent from the following detailed description of severalembodiments which proceeds with reference to the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-3 show an exemplary embodiment of a prosthetic heart valve.

FIGS. 4-10 show an exemplary frame of the prosthetic heart valve of FIG.1.

FIGS. 11-12 show an exemplary inner skirt of the prosthetic heart valveof FIG. 1.

FIG. 13 shows another embodiment of a prosthetic heart valve with adeformed frame.

FIG. 14 shows the prosthetic heart valve of FIG. 1 in a collapsedconfiguration and mounted on an exemplary balloon catheter.

FIGS. 15-17 show the assembly of the inner skirt of FIG. 11 with theframe of FIG. 4.

FIGS. 18-19 show the assembly of an exemplary leaflet structure.

FIG. 20 shows the assembly of commissure portions of the leafletstructure with window frame portions of the frame.

FIGS. 21-22 show the assembly of the leaflet structure with the innerskirt along a lower edge of the leaflets.

FIG. 23 shows a flattened view of an exemplary outer skirt.

FIG. 24 shows another exemplary embodiment of an outer skirt.

FIGS. 25-27 show various views of another exemplary embodiment of anouter skirt.

FIG. 28 shows a schematic view of a portion of the frame and the outerskirt of the prosthetic valve of FIG. 1 with the frame in an expandedconfiguration.

FIG. 29 shows a schematic view of the frame and the outer skirt of FIG.28 with the frame in a collapsed configuration.

FIG. 30 shows another exemplary embodiment of an outer skirt.

DETAILED DESCRIPTION

For purposes of this description, certain aspects, advantages, and novelfeatures of the embodiments of this disclosure are described herein. Thedescribed methods, systems, and apparatus should not be construed aslimiting in any way. Instead, the present disclosure is directed towardall novel and nonobvious features and aspects of the various disclosedembodiments, alone and in various combinations and sub-combinations withone another. The disclosed methods, systems, and apparatus are notlimited to any specific aspect, feature, or combination thereof, nor dothe disclosed methods, systems, and apparatus require that any one ormore specific advantages be present or problems be solved.

Features, integers, characteristics, compounds, chemical moieties, orgroups described in conjunction with a particular aspect, embodiment orexample of the invention are to be understood to be applicable to anyother aspect, embodiment or example described herein unless incompatibletherewith. All of the features disclosed in this specification(including any accompanying claims, abstract, and drawings), and/or allof the steps of any method or process so disclosed, may be combined inany combination, except combinations where at least some of suchfeatures and/or steps are mutually exclusive. The invention is notrestricted to the details of any foregoing embodiments. The inventionextends to any novel one, or any novel combination, of the featuresdisclosed in this specification (including any accompanying claims,abstract, and drawings), or to any novel one, or any novel combination,of the steps of any method or process so disclosed.

Although the operations of some of the disclosed methods are describedin a particular, sequential order for convenient presentation, it shouldbe understood that this manner of description encompasses rearrangement,unless a particular ordering is required by specific language set forthbelow. For example, operations described sequentially may in some casesbe rearranged or performed concurrently. Moreover, for the sake ofsimplicity, the attached figures may not show the various ways in whichthe disclosed methods, systems, and apparatus can be used in conjunctionwith other systems, methods, and apparatus.

As used herein, the terms “a”, “an”, and “at least one” encompass one ormore of the specified element. That is, if two of a particular elementare present, one of these elements is also present and thus “an” elementis present. The terms “a plurality of” and “plural” mean two or more ofthe specified element.

As used herein, the term “and/or” used between the last two of a list ofelements means any one or more of the listed elements. For example, thephrase “A, B, and/or C” means “A”, “B”, “C”, “A and B”, “A and C”, “Band C”, or “A, B, and C”.

As used herein, the term “coupled” generally means physically coupled orlinked and does not exclude the presence of intermediate elementsbetween the coupled items absent specific contrary language.

FIGS. 1-3 show various views of a prosthetic heart valve 10, accordingto one embodiment. The illustrated prosthetic valve is adapted to beimplanted in the native aortic annulus, although in other embodiments itcan be adapted to be implanted in the other native annuluses of theheart (e.g., the pulmonary, mitral, and tricuspid valves). Theprosthetic valve can also be adapted to be implanted in other tubularorgans or passageways in the body. The prosthetic valve 10 can have fourmain components: a stent or frame 12, a valvular structure 14, an innerskirt 16, and a perivalvular sealing means or sealing member. Theprosthetic valve 10 can have an inflow end portion 15, an intermediateportion 17, and an outflow end portion 19. In the illustratedembodiment, the perivalvular sealing means comprises an outer skirt 18.

The valvular structure 14 can comprise three leaflets 40, collectivelyforming a leaflet structure, which can be arranged to collapse in atricuspid arrangement, as best shown in FIG. 2. The lower edge ofleaflet structure 14 desirably has an undulating, curved scalloped shape(suture line 154 shown in FIG. 22 tracks the scalloped shape of theleaflet structure). By forming the leaflets with this scallopedgeometry, stresses on the leaflets are reduced, which in turn improvesdurability of the prosthetic valve. Moreover, by virtue of the scallopedshape, folds and ripples at the belly of each leaflet (the centralregion of each leaflet), which can cause early calcification in thoseareas, can be eliminated or at least minimized. The scalloped geometryalso reduces the amount of tissue material used to form leafletstructure, thereby allowing a smaller, more even crimped profile at theinflow end of the prosthetic valve. The leaflets 40 can be formed ofpericardial tissue (e.g., bovine pericardial tissue), biocompatiblesynthetic materials, or various other suitable natural or syntheticmaterials as known in the art and described in U.S. Pat. No. 6,730,118,which is incorporated by reference herein.

The bare frame 12 is shown in FIG. 4. The frame 12 can be formed with aplurality of circumferentially spaced slots, or commissure windows, 20(three in the illustrated embodiment) that are adapted to mount thecommissures of the valvular structure 14 to the frame, as described ingreater detail below. The frame 12 can be made of any of varioussuitable plastically-expandable materials (e.g., stainless steel, etc.)or self-expanding materials (e.g., nickel titanium alloy (NiTi), such asnitinol) as known in the art. When constructed of aplastically-expandable material, the frame 12 (and thus the prostheticvalve 10) can be crimped to a radially collapsed configuration on adelivery catheter and then expanded inside a patient by an inflatableballoon or equivalent expansion mechanism. When constructed of aself-expandable material, the frame 12 (and thus the prosthetic valve10) can be crimped to a radially collapsed configuration and restrainedin the collapsed configuration by insertion into a sheath or equivalentmechanism of a delivery catheter. Once inside the body, the prostheticvalve can be advanced from the delivery sheath, which allows theprosthetic valve to expand to its functional size.

Suitable plastically-expandable materials that can be used to form theframe 12 include, without limitation, stainless steel, a biocompatible,high-strength alloys (e.g., a cobalt-chromium or anickel-cobalt-chromium alloys), polymers, or combinations thereof. Inparticular embodiments, frame 12 is made of anickel-cobalt-chromium-molybdenum alloy, such as MP35N® alloy (SPSTechnologies, Jenkintown, Pa.), which is equivalent to UNS R30035 alloy(covered by ASTM F562-02). MP35N® alloy/UNS R30035 alloy comprises 35%nickel, 35% cobalt, 20% chromium, and 10% molybdenum, by weight. It hasbeen found that the use of MP35N® alloy to form frame 12 providessuperior structural results over stainless steel. In particular, whenMP35N® alloy is used as the frame material, less material is needed toachieve the same or better performance in radial and crush forceresistance, fatigue resistances, and corrosion resistance. Moreover,since less material is required, the crimped profile of the frame can bereduced, thereby providing a lower profile prosthetic valve assembly forpercutaneous delivery to the treatment location in the body.

Referring to FIGS. 4 and 5, the frame 12 in the illustrated embodimentcomprises a first, lower row I of angled struts 22 arranged end-to-endand extending circumferentially at the inflow end of the frame; a secondrow II of circumferentially extending, angled struts 24; a third row IIIof circumferentially extending, angled struts 26; a fourth row IV ofcircumferentially extending, angled struts 28; and a fifth row V ofcircumferentially extending, angled struts 32 at the outflow end of theframe. A plurality of substantially straight axially extending struts 34can be used to interconnect the struts 22 of the first row I with thestruts 24 of the second row II. The fifth row V of angled struts 32 areconnected to the fourth row IV of angled struts 28 by a plurality ofaxially extending window frame portions 30 (which define the commissurewindows 20) and a plurality of axially extending struts 31. Each axialstrut 31 and each frame portion 30 extends from a location defined bythe convergence of the lower ends of two angled struts 32 to anotherlocation defined by the convergence of the upper ends of two angledstruts 28. FIGS. 6, 7, 8, 9, and 10 are enlarged views of the portionsof the frame 12 identified by letters A, B, C, D, and E, respectively,in FIG. 5.

Each commissure window frame portion 30 mounts a respective commissureof the leaflet structure 14. As can be seen each frame portion 30 issecured at its upper and lower ends to the adjacent rows of struts toprovide a robust configuration that enhances fatigue resistance undercyclic loading of the prosthetic valve compared to known, cantileveredstruts for supporting the commissures of the leaflet structure. Thisconfiguration enables a reduction in the frame wall thickness to achievea smaller crimped diameter of the prosthetic valve. In particularembodiments, the thickness T of the frame 12 (FIG. 4) measured betweenthe inner diameter and outer diameter is about 0.48 mm or less.

The struts and frame portions of the frame collectively define aplurality of open cells of the frame. At the inflow end of the frame 12,struts 22, struts 24, and struts 34 define a lower row of cells definingopenings 36. The second, third, and fourth rows of struts 24, 26, and 28define two intermediate rows of cells defining openings 38. The fourthand fifth rows of struts 28 and 32, along with frame portions 30 andstruts 31, define an upper row of cells defining openings 40. Theopenings 40 are relatively large and are sized to allow portions of theleaflet structure 14 to protrude, or bulge, into and/or through theopenings 40 when the frame 12 is crimped in order to minimize thecrimping profile.

As best shown in FIG. 7, the lower end of the strut 31 is connected totwo struts 28 at a node or junction 44, and the upper end of the strut31 is connected to two struts 32 at a node or junction 46. The strut 31can have a thickness S1 that is less than the thicknesses S2 of thejunctions 44, 46. The junctions 44, 46, along with junctions 64, preventfull closure of openings 40. FIG. 14 shows the prosthetic valve 10crimped on a balloon catheter. As can be seen, the geometry of thestruts 31, and junctions 44, 46, and 64 assists in creating enough spacein openings 40 in the collapsed configuration to allow portions of theprosthetic leaflets to protrude or bulge outwardly through openings.This allows the prosthetic valve to be crimped to a relatively smallerdiameter than if all of the leaflet material were constrained within thecrimped frame.

The frame 12 is configured to reduce, to prevent, or to minimizepossible over-expansion of the prosthetic valve at a predeterminedballoon pressure, especially at the outflow end portion 19 of the frame,which supports the leaflet structure 14. In one aspect, the frame isconfigured to have relatively larger angles 42 a, 42 b, 42 c, 42 d, 42 ebetween struts, as shown in FIG. 5. The larger the angle, the greaterthe force required to open (expand) the frame. As such, the anglesbetween the struts of the frame can be selected to limit radialexpansion of the frame at a given opening pressure (e.g., inflationpressure of the balloon). In particular embodiments, these angles are atleast 110 degrees or greater when the frame is expanded to itsfunctional size, and even more particularly these angles are up to about120 degrees when the frame is expanded to its functional size.

In addition, the inflow and outflow ends of a frame generally tend toover-expand more so than the middle portion of the frame due to the“dog-boning” effect of the balloon used to expand the prosthetic valve.To protect against over-expansion of the leaflet structure 14, theleaflet structure desirably is secured to the frame 12 below the upperrow of struts 32, as best shown in FIG. 1. Thus, in the event that theoutflow end of the frame is over-expanded, the leaflet structure ispositioned at a level below where over-expansion is likely to occur,thereby protecting the leaflet structure from over-expansion.

In a known prosthetic valve construction, portions of the leaflets canprotrude longitudinally beyond the outflow end of the frame when theprosthetic valve is crimped if the leaflets are mounted too close to thedistal end of the frame. If the delivery catheter on which the crimpedprosthetic valve is mounted includes a pushing mechanism or stop memberthat pushes against or abuts the outflow end of the prosthetic valve(for example, to maintain the position of the crimped prosthetic valveon the delivery catheter), the pushing member or stop member can damagethe portions of the exposed leaflets that extend beyond the outflow endof the frame. Another benefit of mounting the leaflets at a locationspaced away from the outflow end of the frame is that when theprosthetic valve is crimped on a delivery catheter, the outflow end ofthe frame 12 rather than the leaflets 40 is the proximal-most componentof the prosthetic valve 10. As such, if the delivery catheter includes apushing mechanism or stop member that pushes against or abuts theoutflow end of the prosthetic valve, the pushing mechanism or stopmember contacts the outflow end of the frame, and not leaflets 40, so asto avoid damage to the leaflets.

Also, as can be seen in FIG. 5, the openings 36 of the lowermost row ofopenings in the frame are relatively larger than the openings 38 of thetwo intermediate rows of openings. This allows the frame, when crimped,to assume an overall tapered shape that tapers from a maximum diameterat the outflow end of the prosthetic valve to a minimum diameter at theinflow end of the prosthetic valve. When crimped, the frame 12 has areduced diameter region extending along a portion of the frame adjacentthe inflow end of the frame that generally corresponds to the region ofthe frame covered by the outer skirt 18. In some embodiments, thereduced diameter region is reduced compared to the diameter of the upperportion of the frame (which is not covered by the outer skirt) such thatthe outer skirt 18 does not increase the overall crimp profile of theprosthetic valve. When the prosthetic valve is deployed, the frame canexpand to the generally cylindrical shape shown in FIG. 4. In oneexample, the frame of a 26-mm prosthetic valve, when crimped, had afirst diameter of 14 French at the outflow end of the prosthetic valveand a second diameter of 12 French at the inflow end of the prostheticvalve.

The main functions of the inner skirt 16 are to assist in securing thevalvular structure 14 to the frame 12 and to assist in forming a goodseal between the prosthetic valve and the native annulus by blocking theflow of blood through the open cells of the frame 12 below the loweredge of the leaflets. The inner skirt 16 desirably comprises a tough,tear resistant material such as polyethylene terephthalate (PET),although various other synthetic materials or natural materials (e.g.,pericardial tissue) can be used. The thickness of the skirt desirably isless than about 0.15 mm (about 6 mil), and desirably less than about 0.1mm (about 4 mil), and even more desirably about 0.05 mm (about 2 mil).In particular embodiments, the skirt 16 can have a variable thickness,for example, the skirt can be thicker at least one of its edges than atits center. In one implementation, the skirt 16 can comprise a PET skirthaving a thickness of about 0.07 mm at its edges and about 0.06 mm atits center. The thinner skirt can provide for better crimpingperformances while still providing good perivalvular sealing.

The skirt 16 can be secured to the inside of frame 12 via sutures 70, asshown in FIG. 22. Valvular structure 14 can be attached to the skirt viaone or more reinforcing strips 72 (which collectively can form asleeve), for example thin, PET reinforcing strips, discussed below,which enables a secure suturing and protects the pericardial tissue ofthe leaflet structure from tears. Valvular structure 14 can besandwiched between skirt 16 and the thin PET strips 72 as shown in FIG.21. Sutures 154, which secure the PET strip and the leaflet structure 14to skirt 16, can be any suitable suture, such as Ethibond Excel® PETsuture (Johnson & Johnson, New Brunswick, N.J.). Sutures 154 desirablytrack the curvature of the bottom edge of leaflet structure 14, asdescribed in more detail below.

Known fabric skirts may comprise a weave of warp and weft fibers thatextend perpendicularly to each other and with one set of the fibersextending longitudinally between the upper and lower edges of the skirt.When the metal frame to which the fabric skirt is secured is radiallycompressed, the overall axial length of the frame increases.Unfortunately, a fabric skirt with limited elasticity cannot elongatealong with the frame and therefore tends to deform the struts of theframe and to prevent uniform crimping.

Referring to FIG. 12, in contrast to known fabric skirts, the skirt 16desirably is woven from a first set of fibers, or yarns or strands, 78and a second set of fibers, or yarns or strands, 80, both of which arenon-perpendicular to the upper edge 82 and the lower edge 84 of theskirt. In particular embodiments, the first set of fibers 78 and thesecond set of fibers 80 extend at angles of about 45 degrees (e.g.,15-75 degrees or 30-60 degrees) relative to the upper and lower edges82, 84. For example, the skirt 16 can be formed by weaving the fibers at45 degree angles relative to the upper and lower edges of the fabric.Alternatively, the skirt can be diagonally cut (cut on a bias) from avertically woven fabric (where the fibers extend perpendicularly to theedges of the material) such that the fibers extend at 45 degree anglesrelative to the cut upper and lower edges of the skirt. As further shownin FIG. 12, the opposing short edges 86, 88 of the skirt desirably arenon-perpendicular to the upper and lower edges 82, 84. For example, theshort edges 86, 88 desirably extend at angles of about 45 degreesrelative to the upper and lower edges and therefore are aligned with thefirst set of fibers 78. Therefore the overall general shape of the skirtis that of a rhomboid or parallelogram.

FIG. 13 shows an example of a crimped prosthetic valve with a skirthaving fibers that extend perpendicular to and/or longitudinally betweenthe upper and lower edges of the skirt. During crimping, this fiberorientation can cause the struts to deform non-uniformly. Moreover, whencrimped, the fabric tends to bunch or create bulges of excess materialin certain locations, which limits the minimum crimping profile andprevents uniform crimping.

FIGS. 15 and 16 show the inner skirt 16 after opposing short edgeportions 90, 92 have been sewn together to form the annular shape of theskirt. As shown, the edge portion 90 can be placed in an overlappingrelationship relative to the opposite edge portion 92, and the two edgeportions can be sewn together with a diagonally extending suture line 94that is parallel to short edges 86, 88. The upper edge portion of theinner skirt 16 can be formed with a plurality of projections 96 thatdefine an undulating shape that generally follows the shape or contourof the fourth row of struts 28 immediately adjacent the lower ends ofaxial struts 31. In this manner, as best shown in FIG. 17, the upperedge of the inner skirt 16 can be tightly secured to struts 28 withsutures 70. The inner skirt 16 can also be formed with slits 98 tofacilitate attachment of the skirt to the frame. Slits 98 aredimensioned so as to allow an upper edge portion of the inner skirt 16to be partially wrapped around struts 28 and to reduce stresses in theskirt during the attachment procedure. For example, in the illustratedembodiment, the inner skirt 16 is placed on the inside of frame 12 andan upper edge portion of the skirt is wrapped around the upper surfacesof struts 28 and secured in place with sutures 70. Wrapping the upperedge portion of the inner skirt 16 around struts 28 in this mannerprovides for a stronger and more durable attachment of the skirt to theframe. The inner skirt 16 can also be secured to the first, second,and/or third rows of struts 22, 24, and 26, respectively, with sutures70.

Referring again to FIG. 12, due to the angled orientation of the fibersrelative to the upper and lower edges, the skirt can undergo greaterelongation in the axial direction (i.e., in a direction from the upperedge 82 to the lower edge 84).

Thus, when the metal frame 12 is crimped (as shown in FIG. 14), theinner skirt 16 can elongate in the axial direction along with the frameand therefore provide a more uniform and predictable crimping profile.Each cell of the metal frame in the illustrated embodiment includes atleast four angled struts that rotate towards the axial direction oncrimping (e.g., the angled struts become more aligned with the length ofthe frame). The angled struts of each cell function as a mechanism forrotating the fibers of the skirt in the same direction of the struts,allowing the skirt to elongate along the length of the struts. Thisallows for greater elongation of the skirt and avoids undesirabledeformation of the struts when the prosthetic valve is crimped.

In addition, the spacing between the woven fibers or yarns can beincreased to facilitate elongation of the skirt in the axial direction.For example, for a PET inner skirt 16 formed from 20-denier yarn, theyarn density can be about 15% to about 30% lower than in a typical PETskirt. In some examples, the yarn spacing of the inner skirt 16 can befrom about 60 yarns per cm (about 155 yarns per inch) to about 70 yarnsper cm (about 180 yarns per inch), such as about 63 yarns per cm (about160 yarns per inch), whereas in a typical PET skirt the yarn spacing canbe from about 85 yarns per cm (about 217 yarns per inch) to about 97yarns per cm (about 247 yarns per inch). The oblique edges 86, 88promote a uniform and even distribution of the fabric material alonginner circumference of the frame during crimping so as to reduce orminimize bunching of the fabric to facilitate uniform crimping to thesmallest possible diameter. Additionally, cutting diagonal sutures in avertical manner may leave loose fringes along the cut edges. The obliqueedges 86, 88 help minimize this from occurring. As noted above, FIG. 13shows a crimped prosthetic valve with a typical skirt that has fibersthat run perpendicularly to the upper and lower edges of the skirt.Compared to the construction of a typical skirt (e.g., FIG. 13), theconstruction of the inner skirt 16 (e.g., FIG. 14) avoids undesirabledeformation of the frame struts and provides more uniform crimping ofthe frame.

In alternative embodiments, the skirt can be formed from woven elasticfibers that can stretch in the axial direction during crimping of theprosthetic valve. The warp and weft fibers can run perpendicularly andparallel to the upper and lower edges of the skirt, or alternatively,they can extend at angles between 0 and 90 degrees relative to the upperand lower edges of the skirt, as described above.

The inner skirt 16 can be sutured to the frame 12 at locations away fromthe suture line 154 so that the skirt can be more pliable in that area.This configuration can avoid stress concentrations at the suture line154, which attaches the lower edges of the leaflets to the inner skirt16.

As noted above, the leaflet structure 14 in the illustrated embodimentincludes three flexible leaflets 40 (although a greater or a smallernumber of leaflets can be used). Additional information regarding theleaflets, as well as additional information regarding skirt material,can be found, for example, in U.S. patent application Ser. No.14/704,861, filed May 5, 2015, which is incorporated by reference in itsentirety.

The leaflets 40 can be secured to one another at their adjacent sides toform commissures 122 of the leaflet structure. A plurality of flexibleconnectors 124 (one of which is shown in FIG. 18) can be used tointerconnect pairs of adjacent sides of the leaflets and to mount theleaflets to the commissure window frame portions 30 (FIG. 5).

FIG. 18 shows the adjacent sides of two leaflets 40 interconnected by aflexible connector 124. Three leaflets 40 can be secured to each otherside-to-side using three flexible connectors 124, as shown in FIG. 19.Additional information regarding connecting the leaflets to each other,as well as connecting the leaflets to the frame, can be found, forexample, in U.S. Patent Application Publication No. 2012/0123529, whichis incorporated by reference herein in its entirety.

As noted above, the inner skirt 16 can be used to assist in suturing theleaflet structure 14 to the frame. The inner skirt 16 can have anundulating temporary marking suture to guide the attachment of the loweredges of each leaflet 40. The inner skirt 16 itself can be sutured tothe struts of the frame 12 using sutures 70, as noted above, beforesecuring the leaflet structure 14 to the skirt 16. The struts thatintersect the marking suture desirably are not attached to the innerskirt 16. This allows the inner skirt 16 to be more pliable in the areasnot secured to the frame and minimizes stress concentrations along thesuture line that secures the lower edges of the leaflets to the skirt.As noted above, when the skirt is secured to the frame, the fibers 78,80 of the skirt (see FIG. 12) generally align with the angled struts ofthe frame to promote uniform crimping and expansion of the frame.

FIG. 20 shows one specific approach for securing the commissure portions122 of the leaflet structure 14 to the commissure window frame portions30 of the frame. The flexible connector 124 (FIG. 19) securing twoadjacent sides of two leaflets is folded widthwise and the upper tabportions 112 are folded downwardly against the flexible connector. Eachupper tab portion 112 is creased lengthwise (vertically) to assume anL-shape having an inner portion 142 folded against the inner surface ofthe leaflet and an outer portion 144 folded against the connector 124.The outer portion 144 can then be sutured to the connector 124 along asuture line 146. Next, the commissure tab assembly is inserted throughthe commissure window 20 of a corresponding window frame portion 30, andthe folds outside of the window frame portion 30 can be sutured toportions 144.

FIG. 20 also shows that the folded down upper tab portions 112 can forma double layer of leaflet material at the commissures. The innerportions 142 of the upper tab portions 112 are positioned flat againstlayers of the two leaflets 40 forming the commissures, such that eachcommissure comprises four layers of leaflet material just inside of thewindow frames 30. This four-layered portion of the commissures can bemore resistant to bending, or articulating, than the portion of theleaflets 40 just radially inward from the relatively more-rigidfour-layered portion. This causes the leaflets 40 to articulateprimarily at inner edges 143 of the folded-down inner portions 142 inresponse to blood flowing through the prosthetic valve during operationwithin the body, as opposed to articulating about or proximal to theaxial struts of the window frames 30. Because the leaflets articulate ata location spaced radially inwardly from the window frames 30, theleaflets can avoid contact with and damage from the frame. However,under high forces, the four layered portion of the commissures can splayapart about a longitudinal axis adjacent to the window frame 30, witheach inner portion 142 folding out against the respective outer portion144. For example, this can occur when the prosthetic valve 10 iscompressed and mounted onto a delivery shaft, allowing for a smallercrimped diameter. The four-layered portion of the commissures can alsosplay apart about the longitudinal axis when the balloon catheter isinflated during expansion of the prosthetic valve, which can relievesome of the pressure on the commissures caused by the balloon, reducingpotential damage to the commissures during expansion.

After all three commissure tab assemblies are secured to respectivewindow frame portions 30, the lower edges of the leaflets 40 between thecommissure tab assemblies can be sutured to the inner skirt 16. Forexample, as shown in FIG. 21, each leaflet 40 can be sutured to theinner skirt 16 along suture line 154 using, for example, Ethibond Excel®PET thread. The sutures can be in-and-out sutures extending through eachleaflet 40, the inner skirt 16, and each reinforcing strip 72. Eachleaflet 40 and respective reinforcing strip 72 can be sewn separately tothe inner skirt 16. In this manner, the lower edges of the leaflets aresecured to the frame 12 via the inner skirt 16. As shown in FIG. 21, theleaflets can be further secured to the skirt with blanket sutures 156that extend through each reinforcing strip 72, leaflet 40 and the innerskirt 16 while looping around the edges of the reinforcing strips 72 andleaflets 40. The blanket sutures 156 can be formed from PTFE suturematerial. FIG. 22 shows a side view of the frame 12, leaflet structure14 and the inner skirt 16 after securing the leaflet structure 14 andthe inner skirt 16 to the frame 12 and the leaflet structure 14 to theinner skirt 16.

FIG. 23 shows a flattened view of the outer skirt 18 prior to itsattachment to the frame 12. The outer skirt 18 can be laser cut orotherwise formed from a strong, durable material such as PET or variousother suitable synthetic or natural materials configured to restrictand/or prevent blood-flow therethrough. The outer skirt 18 can comprisea substantially straight lower edge 160 and an upper edge 162 defining aplurality of alternating projections 164 and notches 166, orcastellations. The outer skirt 18 can also comprise a plurality ofopenings 167 (e.g., 12 in the illustrated embodiment) disposed on anintermediate portion 169 (i.e., the portion between the lower and upperedges 160, 162) of the outer skirt 18. The openings 167 are spaced fromthe lower edge 160 and the upper edge 162 such that the material of theouter skirt 18 separates the openings 167 from the lower and upper edges160, 162.

As best shown in FIG. 3, a lower portion 174 of the outer skirt 18 canbe wrapped around the inflow end 15 of the frame 12, and the lower edge160 of the outer skirt 18 can be attached to the lower edge 176 of theinner skirt 16 and/or the frame 12 at the inflow end of the prostheticvalve 10. In some embodiments, the outer skirt 18 can be attached to theinner skirt 16, for example, with sutures or a suitable adhesive.

In lieu of or in addition to sutures, the outer skirt 18 can be attachedto the inner skirt 16, for example, by ultrasonic welding. Ultrasonicwelding can provide several significant advantages. For example,ultrasonic welding can be relatively less time consuming and lessexpensive compared to suturing, while also providing improved strength.

As shown in FIG. 1, each projection 164 of the outer skirt 18 can beattached to the third row III of struts 26 (FIG. 5) of the frame 12. Theupper edges 162 of the projections 164 can, for example, be wrapped overrespective struts 26 of row III and secured with sutures 168.

As can be seen in FIGS. 1-3, the outer skirt 18 is secured to the frame12 such that when the frame is in its expanded configuration (e.g., whendeployed in a subject), there is excess material between the lower edge160 and the upper edge 162 that does not lie flat against the outersurface of the frame 12. The outer skirt 18 can be secured directly toframe 12 and/or indirectly to frame 12, for example, by securing theouter skirt 18 to the inner skirt 16, which is directly secured to theframe 12. In the expanded configuration of the prosthetic valve, thedistance between the upper and lower attachment points of the outerskirt 18 decreases (foreshortens), resulting in radial expansion of theouter skirt 18. Additionally, the excess material between the lower andupper edges of the outer skirt 18 allows the frame 12 to elongateaxially when crimped without any resistance from the outer skirt 18.

The outer skirt 18 can comprise an axial length or height H_(s), whereH_(s) is the height of the outer skirt 18, less the lower portion 174that is wrapped around the inflow end 15 of the frame 12, as best shownin FIGS. 1, 3, and 23. In some embodiments, the height H_(s) can besubstantially the same as the axial length between the upper attachmentpoint of the outer skirt 18 to the frame 12 and the inflow end 15 of theframe 12 when the frame 12 is fully crimped. In such embodiments, whenthe frame 12 is fully crimped, the outer skirt 18 can lie flat againstthe outer surface of the frame 12. In other embodiments, the heightH_(s) of the outer skirt 18 can exceed the axial length between theupper attachment point of the outer skirt 18 to the frame 12 and theinflow end 15 of the frame 12 when the frame 12 is fully crimped. Insuch embodiments, the outer skirt 18 can comprise a plurality of creases170 (e.g., twelve in the illustrated embodiment).

As best shown in FIG. 3, the creases 170 can extend axially from thelower edge 160 toward the intermediate portion 169 of the outer skirt18. The creases 170 can be aligned circumferentially with respectiveprojections 164, and the outer skirt 18 can be oriented with respect tothe frame 12 such that the creases 170 are circumferentially alignedbetween a respective pair of apices 22 a (FIG. 5) that are formed by thestruts 22 at the inflow end 15 of the frame 12. For example, the creases170 can be circumferentially aligned along a respective vertical line172 (FIGS. 2 and 5) that is parallel to the longitudinal axis of theframe 12 and bisects the frame 12 at a location equidistant from eachapex 22 a of a respective pair of apices 22 a. In this manner, thecreases 170 can cause excess material of the outer skirt 18 to retractradially inwardly between the apices 22 a and into the inflow end 15 ofthe frame 12 when the prosthetic valve 10 is crimped from the expandedconfiguration. As best shown in FIG. 2, each crease 170 can becircumferentially aligned with a respective opening 167 and projection164 along a respective line 172.

Referring to FIGS. 28-29, in lieu of or in addition to the creases 170(FIG. 1), the outer skirt 18 can be attached and/or positioned relativeto the frame 12 such that the lower edge 160 of the outer skirt 18contacts the inflow end 15 of the frame 12 at locations (e.g., apices 22a) that are offset relative to locations (e.g., the junctions 64) thatthe upper edge 162 of the outer skirt 18 contacts the outflow end 19 ofthe frame 12. Configuring the outer skirt 18 and the frame 12 in thismanner can cause excess material of the outer skirt 18 to retractinwardly between the apices 22 a of the frame 12 when the prostheticvalve 10 is crimped from the expanded configuration (e.g., FIG. 28) tothe collapsed configuration (e.g., FIG. 29), as shown in FIG. 29.

This configuration also spreads the deformed fabric of the collapsedouter skirt 18 over a relatively large distance, which reduces theamount of outer skirt material per cross sectional area and flattens theouter skirt 18 around the crimped frame 12, thus reducing the crimpedprofile of the prosthetic heart valve 10. Reducing the crimped profileof the prosthetic heart valve 10 can reduce the push force necessary tomove the prosthetic heart valve 10 relative to a patient's vasculatureor a delivery cylinder of a delivery apparatus. It can also reduce thecompression force that is exerted upon the leaflets 40 to achieve aparticular crimp profile, which can reduce and/or eliminate damage tothe leaflets 40 caused by over compressing the leaflets 40 duringcrimping and/or delivery of the prosthetic heart valve 10 to animplantation location.

Retracting the excess material within the frame 12 below the leaflets 40when the prosthetic valve 10 is crimped advantageously allows theprosthetic valve 10 to have a relatively large outer skirt 18, which cansignificantly reduce perivalvular leakage, while minimizing the radialcrimp profile of the prosthetic valve 10. For example, the height H_(s)of the outer skirt 18 can be about 9 mm to about 25 mm or about 13 mm toabout 20 mm, with about 19 mm being a specific example. The height H_(f)of the frame 12 in the radially expanded state can be about 12 mm toabout 27 mm or about 15 mm to about 23 mm, with about 20 mm being aspecific example. The outer skirt 18 can be sized such that a ratioH_(s):H_(f), where H_(s) (FIG. 23) is the height of the outer skirt 18,and H_(f) (FIG. 5) is the height of the frame 12 in the expanded state,can be between about 0.75 to about 0.95. In some embodiments, the ratioH_(s):H_(f) can be between about 0.80 to about 0.90 or about 0.84 toabout 0.87. In one particular embodiment, the ratio H_(s):H_(f) can be0.86.

Providing a relatively larger outer skirt 18 allows the prosthetic valve10 to be positioned in a wider range of positions relative to the nativeannulus, while providing adequate perivalvular sealing. This improvedrange can make the prosthetic valve 10 easier to position during theimplantation procedure. It also allows the prosthetic valve to adapt togreater variation in native annulus anatomy.

In addition, the creases 170 can assist the outer skirt 18 in collapsingin a predetermined, uniform manner when the prosthetic valve is crimped.This uniformity can prevent the outer skirt 18 from bunching or waddingwhen crimping and/or loading the prosthetic valve 10 in a deliveryapparatus, which in turn allows the outer skirt 18 to expand to itsfunctional state more quickly and consistently when deploying theprosthetic valve 10, as further described below.

Each crease 170 can be formed, for example, by overlapping adjacentportions of the outer skirt 18 and securing them together. The creasescan then be secured in the overlapped state, for example, by sutures,ultrasonic welding, and/or an adhesive. The creases 170 can be referredto as permanent creases in that the creases are retained when theprosthetic valve 10 is in a radially compressed state and a radiallyexpanded state.

As best shown in FIG. 23, the openings 167 can be laterally(circumferentially in FIGS. 1-3) spaced apart relative to adjacentopenings 167 and be laterally (circumferentially in FIGS. 1-3) alignedwith a respective projection 164. The openings 167 can also becircumferentially aligned with respective creases 170, as best shown inFIGS. 1 and 3. For example, the projections 164, the openings 167, andthe creases 170 can be aligned along the respective vertical lines 172,as best shown in FIG. 2. Aligning the openings 167 and the creases 170can, for example, allow blood to quickly enter, and thus expand, theoverlapped portions of the outer skirt 18 when the prosthetic valve isinitially deployed, as further described below.

The openings 167 can also advantageously allow back-flowing blood (e.g.,retrograde blood) to enter the outer skirt 18 from a different angle ordirection than the notches 166, thus improving how quickly the outerskirt 18 initially expands and improving perivalvular sealing. Theopenings 167 can be provided in lieu of or in addition to the notches166.

The openings 167 can comprise various shapes. For example, the openings167 can comprise a tear-drop shape, as shown in the illustratedembodiment. In other embodiments, the openings can be circular,elliptical, rectangular, etc.

The prosthetic valve 10 can be configured for and mounted on a suitabledelivery apparatus for implantation in a subject. Several catheter-baseddelivery apparatuses are known; a non-limiting example of a suitablecatheter-based delivery apparatus includes that disclosed in U.S. PatentApplication Publication No. 2013/0030519, which is incorporated byreference herein in its entirety, and U.S. Patent ApplicationPublication No. 2012/0123529.

To implant a plastically-expandable prosthetic valve 10 within apatient, the prosthetic valve 10 including the outer skirt 18 can becrimped on an elongated shaft 180 of a delivery apparatus, as best shownin FIG. 14. The prosthetic valve, together with the delivery apparatus,can form a delivery assembly for implanting the prosthetic valve 10 in apatient's body. The shaft 180 comprises an inflatable balloon 182 forexpanding the prosthetic valve within the body. With the balloon 182deflated, the prosthetic valve 10 can then be percutaneously deliveredto a desired implantation location (e.g., a native aortic valve region).Once the prosthetic valve 10 is delivered to the implantation site(e.g., the native aortic valve) inside the body, the prosthetic valve 10can be radially expanded to its functional state by inflating theballoon 182.

When the prosthetic valve 10 expands, the notches 166 and the openings167 allow blood to flow between the outer skirt 18 and the inner skirt16. This blood-flow causes the excess fabric of the outer skirt 18 tofurther radially expand and separate from the inner skirt 16.

The expanded outer skirt 18 can fill-in gaps between the frame 12 andthe surrounding native annulus to assist in forming a good, fluid-tightseal between the prosthetic valve 10 and the native annulus. The outerskirt 18 therefore cooperates with the inner skirt 16 to avoidperivalvular leakage after implantation of the prosthetic valve 10. Inseveral embodiments, the prosthetic valve 10 comprising the outer skirt18 that expands radially outwardly can have reduced perivalvular leakagewhen implanted in a subject compared to a similar prosthetic valve thathas a relatively smaller outer skirt or lacks the outer skirt 18.

Alternatively, a self-expanding prosthetic valve 10 can be crimped to aradially collapsed configuration and restrained in the collapsedconfiguration by inserting the prosthetic valve 10, including the outerskirt 18, into a sheath or equivalent mechanism of a delivery catheter.The prosthetic valve 10 can then be percutaneously delivered to adesired implantation location. Once inside the body, the prostheticvalve 10 can be advanced from the delivery sheath, which allows theprosthetic valve to expand to its functional state.

When the outer skirt 18 is exposed from the delivery sheath, the notches166 and the openings 167 allow blood to flow between the outer skirt 18and the inner skirt 16. This blood-flow causes the excess fabric of theouter skirt 18 to further radially expand and separate from the innerskirt 16.

FIG. 24 shows an exemplary embodiment of an outer skirt 200. The outerskirt 200 can comprise a first end portion 202 (i.e., the upper endportion as depicted in FIG. 24), a second end portion 204 (i.e., thelower end portion as depicted in FIG. 24), and an intermediate portion206 disposed between the first and second end portions 202, 204.

The first end portion 202 of the outer skirt 200 can include a pluralityof alternating projections 208 and notches 210 and can also include aplurality of first openings 212. The first end portion 202 can beconfigured similar to the projections 164, the notches 166, and theopenings 167 of the outer skirt 18. For example, the first openings 212can be circumferentially aligned with the projections 208 andcircumferentially offset relative to the notches 210. The first endportion 202 can be attached to an inner skirt and/or frame of aprosthetic heart valve, as further described below.

The first openings 212 can comprise various sizes and/or shapes. Forexample, as shown in FIG. 24, the first openings 212 comprise a“tear-drop” shape. In other embodiments, the first openings 212 can belarger (e.g., elongate) or smaller and can comprise various other shapes(e.g., circular, rectangular, or ovular) than those shown in theillustrated embodiment.

The first end portion 202 of the outer skirt 200 can comprise firstouter diameter. In some embodiments, the first, outer diameter of thefirst end portion 202 is at least substantially similar to a second,outer diameter of the second end portion 204 and smaller than a third,outer diameter of the intermediate portion 206. In other embodiments,the first diameter of the first end portion 202 can be smaller than thesecond diameter of the second end portion 204 and the third diameter ofthe intermediate portion 206. In yet other embodiments, the firstdiameter of the first end portion 202 can be larger than the seconddiameter of the second end portion 204 and can be smaller than the thirddiameter of the intermediate portion 206.

The second end portion 204 of the outer skirt 200 can comprise asubstantially straight lower edge 214. The second end portion 204 can beattached to an inner skirt and/or frame of a prosthetic heart valve, asfurther described below. The second diameter of the second end portioncan be smaller than the third diameter of the intermediate portion 206.

The intermediate portion 206 of the outer skirt 200 can comprise a bulgeextending radially outwardly to the third diameter relative to the firstand second end portions 202, 204. The intermediate portion 206 cancomprise a radially outwardly facing surface 216. As shown, in someembodiments, the surface 216 can be relatively flat. In otherembodiments, the surface 216 can be relatively tapered, from the firstend portion 202 to the second end portion 204, or vice versa. In yetother embodiments, the surface 216 can be relatively curved or rounded.

In some embodiments, the surface 216 of the intermediate portion 206 cancomprise a plurality of second openings 217. The second openings 217 canbe spaced apart relative to each other, circumferentially aligned withthe notches 210 of the first end portion 202, and circumferentiallyoffset relative to the first openings 212 and the projections 208 of thefirst end portion 202. The second openings 217 can comprise variousshapes and/or sizes, including diamond-shaped (as shown in FIG. 24),circular, rectangular, ovular, etc. In alternative embodiments, thesurface 216 can be formed without the second openings 217.

The intermediate portion 206 can also comprise first and secondtransition sections 218, 220 separated relative to each other by thesurface 216 and disposed adjacent to the first and second end portions202, 204, respectively. In some embodiments, the transition sections218, 220 can be at least substantially perpendicular to the surface 216.In such embodiments, the outer diameter of the outer skirt 200 abruptlytransitions from the respective first and second diameters of the firstand second end portions 202, 204 to the third diameter of theintermediate portion 206 in a step- or flange-like manner. In otherembodiments, the transition sections 218, 220 can be angled between therespective end portions 202, 204 and the surface 216 such that the outerdiameter of the outer skirt 200 tapers from the respective first andsecond diameters of the end portions 202, 204 to the third diameter ofthe intermediate portion 206.

The outer skirt 200 can be coupled to a frame and/or an inner skirt of aprosthetic heart valve similar to the manner in which the outer skirt 18is coupled to the frame 12 and/or the inner skirt 16 of the prostheticheart valve 10. For example, the outer skirt 200 can be attached to aframe and/or inner skirt of a prosthetic heart valve by sutures and/orultrasonic welding.

The outer skirt 200 can be formed of materials such as PET, PTFE, ePTFE,polyurethane, polyester, and/or other suitable materials configured torestrict and/or prevent blood-flow therethrough. In some embodiments,the outer skirt 200 can be formed from a generally flat strip (e.g.,similar to the outer skirt 18 as shown in FIG. 23) and formed into atube by welding the ends together, as shown in FIG. 24. In otherembodiments, the outer skirt 200 formed by weaving the outer skirt 200into a tubular shape. The bulge in the intermediate portion 206 can beformed, for example, by shape-setting the material to a desiredconfiguration (e.g., as shown in FIG. 24).

The outer skirt 200 can be configured to be radially compressed to adelivery configuration and to radially expand from the deliveryconfiguration to a function configuration, in a manner similar to theouter skirt 18. In some embodiments, the outer skirt 200 can beself-expandable, such as by including Nitinol threads in the outer skirt200. Additionally or alternatively, the outer skirt 200 can be expandedby blood flowing into the outer skirt 200 through the notches 210 and/orthe openings 212.

In this manner, the outer skirt 200 in conjunction with the inner skirt16 can reduce and/or eliminate perivalvular leakage between a frame of aprosthetic heart valve and a native annulus. As a result, the outerskirt 200 can improve functionality of a prosthetic heart valve and thusimprove functionality of a patient's heart.

FIGS. 25-27 show an exemplary embodiment of an outer skirt 300. FIG. 25shows a flattened view of the outer skirt 300 prior to its attachment toa prosthetic heart valve. FIGS. 26-27 show the outer skirt 300 attachedto the prosthetic heart valve 10 in lieu of outer skirt 18.

Referring to FIG. 25, the outer skirt 300 can comprise a first endportion 302 (i.e., the upper end portion as depicted in FIG. 25), asecond end portion 304 (i.e., the lower end portion as depicted in FIG.25), and an intermediate portion 306 disposed between the first andsecond end portions 302, 304. The first end portion 302 of the outerskirt 300 can include a plurality of alternating projections 308 andnotches 310, or castellations. The second end portion 304 of the outerskirt 300 can comprise a substantially straight lower edge 312 and canhave a plurality of openings 314. The openings 314 can be laterallyspaced apart relative to each other and laterally aligned with theprojections 308 of the first end portion 302 and laterally offsetrelative to the notches 310 of the first end portion 302. The openings314 can comprise various sizes and/or geometric shapes, includingcircular, ovular, rectangular, and/or combinations of shapes.

Referring to FIG. 26, the projections 308 of the first end portion 302can be attached to the inner skirt 16 and/or the frame 12 of theprosthetic heart valve 10 using sutures (as shown) and/or ultrasonicwelding. As shown in FIG. 27, the lower edge 312 of the second endportion 304 can be attached to the inner skirt 16 and/or the frame 12 ofthe prosthetic heart valve 10 using sutures (as shown) and/or ultrasonicwelding.

The outer skirt 300 can be formed of materials such as PET, PTFE, ePTFE,polyurethane, polyester, and/or other suitable materials configured torestrict and/or prevent blood-flow therethrough.

The outer skirt 300 can reduce and/or eliminate perivalvular leakagewhen the prosthetic heart valve 10 is implanted in a native heart valveannulus (e.g., a native aortic valve annulus or a native mitral valveannulus). For example, blood flowing from the inflow end portion 15(FIG. 27) toward the outflow end portion 19 (FIG. 26) of the prostheticheart valve 10 (i.e., antegrade blood flow) can enter the outer skirt300 through the openings 314 of the second end portion 304, as bestshown FIG. 27. Similarly, blood flowing from the outflow end portion 19toward the inflow end portion 15 of the prosthetic heart valve 10 (i.e.,retrograde blood flow) can enter the outer skirt 300 through the notches310 of the first end portion 302, as best shown in FIG. 26. Theblood-flow entering the openings 314 and/or the notches 310 cannot passdirectly through the outer skirt 300 because the openings 314 and thenotches 310 are circumferentially offset relative to each other. As aresult, the outer skirt 300 expands radially outwardly and seals and/orreduces gaps between the prosthetic heart valve 10 and the nativeannulus, thereby reducing and/or eliminating perivalvular leakage inconjunction with the inner skirt 16.

FIG. 30 shows an exemplary embodiment of an outer skirt 400. The outerskirt 400 can be configured similar to the outer skirt 18 of theprosthetic heart valve 10 and can be attached to the prosthetic heartvalve 10 in a manner similar to the outer skirt 18. In some embodimentsand in lieu of or in addition to creases at the inflow end portion 15 ofthe prosthetic heart valve 10 (e.g., the creases 170 of the outer skirt18), the outer skirt 400 can have creases 402 extending axially from afirst end portion 404 of the outer skirt 400 to a second end portion 406of the outer skirt 400. The creases 402 can be circumferentially alignedwith notches 408 and circumferentially offset relative to projections410 of the first end portion 404.

In this manner, the outer skirt 400 can expand from a compressedconfiguration to an expanded configuration (and vice versa) in a uniformand/or predictable manner, similar to a bellows or an accordion. As aresult, the creases 402 facilitate uniform crimping and/or expansionand/or reduce the crimped radial profile of a prosthetic heart valve incompressed delivery configuration.

In some embodiments, the outer skirt 400 can comprise one or more reedsor valves configured to allow blood to flow into and/or through theouter skirt 400. For example, the outer skirt 400 can comprise a flapthat is configured to selectively allow blood to flow into and/orthrough the outer skirt 400.

The outer skirt 400 can be formed, for example, by shape setting theouter skirt in this manner. In some embodiments, the creases 402 can beformed by ultrasonic welding.

It should be noted that, in some embodiments, the outer skirts 200, 300can comprise creases similar to the creases 170, 402 of the outer skirt18. The creases can be configured to facilitate uniform crimping and/orexpansion and/or to reduce the crimped radial profile of a prostheticheart valve in compressed delivery configuration. In some embodiments,the creases can be formed by ultrasonic welding.

It should also be noted that the features of any embodiment can becombined with one or more of the features of any other embodiment orembodiment. For example, in some embodiments, an outer skirt cancomprise the creases 170 of the outer skirt 18 and the creases 402 ofthe outer skirt 400.

In view of the many possible embodiments to which the principles of thedisclosed invention may be applied, it should be recognized that theillustrated embodiments are only examples of the invention and shouldnot be taken as limiting the scope of the invention. Rather, the scopeof the invention is defined by the following claims. We therefore claimas our invention all that comes within the scope of these claims.

1. A prosthetic heart valve comprising: an annular frame being movablebetween a radially collapsed configuration and a radially expandedconfiguration, the annular frame comprising: an inflow end; an outflowend; a plurality of struts disposed between the inflow end and theoutflow end; a plurality of apices disposed at the inflow end formed byintersections of two or more of the plurality of struts; and a pluralityof junctions disposed between the plurality of apices and the outflowend and formed by intersections of two or more of the plurality ofstruts, wherein the plurality of apices is circumferentially offset fromthe plurality of junctions; a leaflet structure positioned within andsecured to the annular frame, wherein the leaflet structure isconfigured to allow one-way blood flow from the inflow end to theoutflow end; and an annular skirt secured to the annular frame, whereinthe annular skirt comprises: a first edge portion secured to the annularframe at the plurality of apices; and a second edge portion secured tothe annular frame at the plurality of junctions, wherein the annularskirt is configured to retract radially inwardly between the pluralityof apices when the annular frame is moved from the radially expandedconfiguration to the radially collapsed configuration.
 2. The prostheticheart valve of claim 1, wherein the annular skirt is formed of apolyurethane material.
 3. The prosthetic heart valve of claim 1, whereinthe annular skirt is formed of a cloth material.
 4. The prosthetic heartvalve of claim 1, wherein the second edge portion of the annular skirthas an undulating profile.
 5. The prosthetic heart valve of claim 4,wherein the undulating profile of the annular skirt comprises aplurality of projections and notches.
 6. A prosthetic heart valvecomprising: a frame comprising an inflow end and an outflow end andbeing movable from a radially collapsed configuration to a radiallyexpanded configuration; a valvular structure positioned within andsecured to the frame, wherein the valvular structure comprises aplurality of leaflets movable between an open configuration and a closedconfiguration, wherein in the open configuration blood flow is permittedfrom the inflow end to the outflow end, and wherein in the closedconfiguration blood flow is restricted from the outflow end to theinflow end; and a skirt positioned around an outer surface of the frame,wherein the skirt comprises: a first edge portion secured to the frameat a plurality of first circumferential attachment points of the frame;and a second edge portion secured to the frame at a plurality of secondcircumferential attachment points of the frame, wherein the plurality offirst circumferential attachment points is circumferentially offset andspaced longitudinally relative to the plurality of secondcircumferential attachment points.
 7. The prosthetic heart valve ofclaim 6, wherein the frame comprises: a plurality of struts disposedbetween the inflow end and the outflow end; a plurality of apicesdisposed at the inflow end and formed by intersections of two or morestruts of the plurality of the struts, wherein the plurality of firstcircumferential attachment points is disposed at the plurality ofapices; and a plurality of junctions disposed between the plurality ofapices and the outflow end and formed by intersections of two or morestruts of the plurality the struts, wherein the plurality of secondcircumferential attachment points is disposed at the plurality ofjunctions, and wherein the plurality of junctions is circumferentiallyoffset relative to the plurality of apices.
 8. The prosthetic heartvalve of claim 7, wherein the skirt is configured such that the skirtretracts radially inwardly between the plurality of apices when theframe is moved from the radially expanded configuration to the radiallycollapsed configuration.
 9. The prosthetic heart valve of claim 7,wherein the plurality of apices is a first plurality of apices disposedat the inflow end, wherein the frame further comprises a secondplurality of apices disposed at the outflow end, and wherein theplurality of junctions is circumferentially aligned with the pluralityof second apices.
 10. The prosthetic heart valve of claim 7, whereineach of the plurality of first circumferential attachment pointscorresponds to a respective apex of the plurality of apices at theinflow end.
 11. The prosthetic heart valve of claim 7, wherein each ofthe plurality of second circumferential attachment points corresponds toa respective junction of the plurality of junctions.
 12. The prostheticheart valve of claim 6, wherein the second edge portion of the skirt hasan undulating profile.
 13. The prosthetic heart valve of claim 6,wherein the skirt is formed of a polyurethane material.
 14. A prostheticheart valve comprising: an annular frame being movable between aradially collapsed configuration and a radially expanded configuration,the annular frame comprising: an inflow end; an outflow end; alongitudinal axis extending from the inflow end to the outflow end; anda plurality of struts disposed between the inflow end and the outflowend; a valvular structure positioned within and secured to the annularframe and configured to allow one-way blood flow from the inflow end tothe outflow end; and an annular skirt positioned around and secured tothe annular frame and comprising: a first edge portion disposed at oradjacent the inflow end of the annular frame, wherein the first edgeportion of the annular skirt is attached to the annular frame at a firstplurality of circumferential attachment points of the annular frame; anda second edge portion disposed toward the outflow end of the annularframe relative to the first edge portion, wherein the second edgeportion of the annular skirt is attached to the annular frame at asecond plurality of circumferential attachment points of the annularframe, and wherein the first plurality of circumferential attachmentpoints is circumferentially offset relative to the second plurality ofcircumferential attachment points.
 15. The prosthetic heart valve ofclaim 14, wherein each of the second plurality of circumferentialattachment points corresponds to a respective strut of the plurality ofstruts, and wherein each respective strut of the plurality of struts isoriented parallel to the longitudinal axis of the annular frame.
 16. Theprosthetic heart valve of claim 14, wherein each of the second pluralityof circumferential attachment points corresponds to a respective strutof the plurality of struts, and wherein each respective strut of theplurality of struts is oblique relative to the longitudinal axis of theannular frame.
 17. The prosthetic heart valve of claim 14, wherein theannular frame further comprises a plurality of apices at the outflow endof the annular frame formed by intersections of two or more struts ofthe plurality of struts, and wherein the plurality of apices at theoutflow end forms the first plurality of circumferentially attachmentpoints.
 18. The prosthetic heart valve of claim 14, wherein the annularframe further comprises a plurality of junctions disposed between theinflow end of the annular frame and the outflow end of the annular frameformed by intersections of two or more struts of the plurality ofstruts, and wherein the plurality of junctions forms the secondplurality of circumferential attachment points.
 19. The prosthetic heartvalve of claim 14, wherein the annular skirt is attached to the annularframe with sutures.
 20. The prosthetic heart valve of claim 14, wherein:the annular frame further comprises a plurality of apices at the inflowend of the annular frame formed by intersections of two or more strutsof the plurality of struts, the first edge portion of the annular frameis configured to cover the apices at the inflow end of the annularframe, and wherein the first plurality of circumferential attachmentpoints is disposed on an inside surface of the annular frame.